The present invention is directed to gas compressors used in an aeropropulsion jet engine for propelling a vehicle by means of thrust generated by the engine. More particularly, it relates to a jet engine having a structure designated for operation at supersonic or hypersonic flight velocities.
The operation of conventional turbojet and turbofan engines at flight Mach numbers exceeding Mach 3.5 is severely constrained by limitations imposed on compressor outlet and turbine inlet temperatures. Ramjet engines, however, may be operated efficiently at flight velocities ranging from Mach 1.5 to Mach 6-7 above which dissociation effects prevent effective fuel utilization. Supersonic combustion ramjet engines (SCRAMJET) are potentially operable up to orbital velocities. Both types of ramjet engines suffer from major difficulties. No usable thrust is produced at flight velocities less than about Mach 0.8 for Ramjets and below Mach 4 for a Scramjet. Traditional methods of dealing with the problem use a secondary propulsion system, either expendable or reusable, to accelerate the vehicle to an appropriate starting velocity for the Ramjet or Scramjet. The use of a secondary propulsion system increases the weight and complexity of the engine and limits its operational flexibility. Typical of prior art arrangements are the devices disclosed in U.S. Pat. Nos. 2,920,448, 3,323,304, 3,374,631, 3,382,679, 3,750,400, 3,800,529, 3,800,531, 4,379,679 and applicant's patent 4,644,746. Also of some relevance is French Patent No. 2,534,983.